In recent years, rechargeable and dischargeable energy storage devices have been adopted as power sources of vehicles (such as an automobile and a motorcycle) and various devices (such as a portable terminal and a laptop computer). The energy storage devices include, for example, batteries (such as a lithium ion battery and a nickel-hydrogen cell) or capacitors (such as an electric double layer capacitor)
For example, the battery includes an electrode assembly and a case. The case includes a case body, which houses the electrode assembly, and a cover plate, which covers an opening of the case body. The electrode assembly and a current collector, which is coupled to the electrode assembly, are disposed within the case. An external terminal is disposed, for example, on an outer surface of the cover plate. The external terminal and the current collector are directly or indirectly coupled together. This electrically couples the external terminal and the electrode assembly together.
As a member that electrically couples the external terminal and the current collector, for example, a conductive member is used. The conductive member includes, for example, a body, an auxiliary terminal, and a coupling conductor. The auxiliary terminal includes a first swage portion, which protrudes from a lower surface of the body, and a second swage portion, which protrudes from a top surface of the body. The coupling conductor includes two through holes. The second swage portion of the auxiliary terminal is inserted into one through hole. A shaft portion of the external terminal is inserted into the other through hole.
A battery described in JP-A-2010-097764 (Patent Literature 1) includes an auxiliary terminal (8), an external terminal (4), and a coupling conductor (9). The auxiliary terminal includes a body (a pedestal portion (8a)), a first swage portion (a first swage tube (8b)), and a second swage portion (a second swage tube (8c)). The external terminal (4) includes a head (a pedestal portion (4a)) and a male threaded portion (a bolt portion (4b)). The coupling conductor (9) includes through holes (a swage hole (9a) and a terminal through hole (9b)).
The auxiliary terminal is disposed on an outer surface of a cover plate (3) via a sealing member (an external insulation sealing member (6)). This allows insertion of the first swage portion of the auxiliary terminal into a through hole of a current collector (a current collecting connector (5)) within a case. A distal end of the first swage portion that protrudes downward from the through hole is swaged from a lower side.
The external terminal is disposed on the outer surface of the cover plate via the sealing member or a terminal retainer disposed separately from the sealing member. The second swage portion of the auxiliary terminal and the male threaded portion of the external terminal are inserted into the respective through holes of the coupling conductor. A distal end of the second swage portion that protrudes upward from the one through whole (the swage hole (9a)) is swaged from an upper side. This electrically couples the external terminal and the current collector together via the auxiliary terminal and the coupling conductor.
Incidentally, in the battery described in Patent Literature 1, the second swage portion inserted into the through hole of the coupling conductor is swaged. This swaging integrates the auxiliary terminal and the coupling conductor together. Subsequently, the first swage portion is inserted into a wall surface (partition) of the case. The first swage portion, which is inserted into the wall surface of the case and the through hole of the current collector, is swaged. At this time, the auxiliary terminal and the coupling conductor, which are integrated together, may be rotated around a rotation axis in the insertion direction by a swaging force generated when the first swage portion is swaged. Thus, the coupling conductor may be displaced from a desired position.
This type of problem may occur not only in batteries but also in capacitors (such as a double layer capacitor) as well.